1. Field of the Invention
The present invention relates to a device for the simultaneous transmission of two data signals over the same line in opposite directions.
2. Description of the Prior Art
The most common method of allowing two electronic modules to communicate with each other via simultaneous bi-directional (full duplex) data flow is by connecting them together with two electrical lines, one for data transmission in each direction. In an effort to reduce the number of electrical lines connecting electronic devices, and consequently the number of pins or terminals on an electronic device devoted to this communication, technology has been developed to allow for the transmission of two data sequences in opposite directions over the same communication line.
Two ways of doing this are frequency multiplexing, and time multiplexing. Frequency multiplexing is not at all useful when dealing with standard logic levels within a circuit, and time multiplexing is inherently slow, due to the fact that you can only send one signal in one direction at a time.
To overcome these problems, technology has been developed to allow two electrical circuits to communicate with each other over a single electrical interconnect in both directions at the same time. Past technology for doing this has been slow in terms of switching rate, required considerable power consumption, and/or required impedance matching with the transmission line, all of which are not desirable.
It is an object of the present invention to provide a means for simultaneous full duplex communication over a single electrical interconnect at standard CMOS logic levels and thresholds.
It is also an object of the present invention to provide this communication without making speed power ratio sacrifices, or requiring a matched line impedance.